|Publication number||US4825869 A|
|Application number||US 07/101,757|
|Publication date||2 May 1989|
|Filing date||28 Sep 1987|
|Priority date||28 Sep 1987|
|Publication number||07101757, 101757, US 4825869 A, US 4825869A, US-A-4825869, US4825869 A, US4825869A|
|Inventors||Louis Sasmor, Edward D. Smith|
|Original Assignee||Telectronics N.V.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (4), Non-Patent Citations (12), Referenced by (229), Classifications (6), Legal Events (10)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present invention concerns a novel system for gathering and processing information for the purpose of determining whether or not an implanted cardiac pacer system is functioning properly.
Modern implanted cardiac pacers have the ability to telemeter information to an external programming and/or receiving unit. In this manner, certain information concerning the pacer's characteristics, including mode, rate, battery level, etc. can be obtained. It is very desirable to be able to determine whether the implanted pacer is functioning properly; specifically, to determine whether the implanted pacer is supporting the patient as expected, given the pacer therapy described and programmed by the implanting or patient follow-up clinician. It would be extremely desirable to have the ability to analyze complex pacemaker modified electrocardiograms (ECGs), determine problems, relate the problems to the specific causes, and have the ability to recommend clinically acceptable actions.
In accordance with the present invention, a cardiac pacer analysis system is provided which non-invasively performs a detailed analysis of the functional status of the entire implanted pacemaker/patient system, rather than merely providing an annotated display of the ECG. The illustrative embodiment combines the surface ECG with telemetered atrial and ventricular ICEGs and activity indicators into a common structure for the simultaneous analyses of pacing antifacts to verify pacemaker output, of evoked potentials to verify capture, and of spontaneous cardiac activity to verify pacemaker sensing. It incorporates a detailed model of the specific pacemaker, and adjusts the actions of the model based on telemetered pacemaker programmed parameter values.
The illustrative embodiment analyzes the functions of and identifies problems with the entire pacemaker system, including the leads and the pacemaker's interactions with the patient. It combines the abnormal functionings observed on different beats into a structure of common underlying problem causes, using a knowledge base which includes both clinical and engineering expertise. It incorporates information stored in and telemetered from the pacemaker (such as lead location and implant date) as well as the telemetered results of automatically performed pacemaker measurements (such as battery voltage and lead impedance) in identifying problems.
The illustrative embodiment uses its clinically derived knowledge base plus patient and pacemaker information to recommend specific corrective actions that could be taken to rectify problems that have been identified.
The illustrative embodiment provides an English language annotated description of the analysis results, along with conventional graphics ECGs.
The illustrative embodiment receives data about the pacemaker and its interaction with the patient from both surface ECG signals and telemetric communications with the pacemaker. The telemetered data include programmed parameter vales, atrial and ventricular intra-cardiac electrograms, pacemaker activity indicators, the results of automatically performed pacemaker measurements, and patient history informaation previously stored in the pacemaker. These data are combined with a pre-stored knowledge base which encompasses the functional characteristics of the implanted pacemaker and the clinical interpretation of paced cardiac events.
The illustrative embodiment uses these data as information about the specific pacemaker/patient interactions, and via a combination of digital signal processing, emulation (modeling) of the pacemaker functions, and application of published and rules-of-thumb heuristic clinical interpretations of paced cardiac events, produces a comprehensive analysis of a patient's pacemaker modified ECG. It identifies normal and abnormal functional events, and summarizes these for the clinician; for any abnormal events, it identifies probable causes and lists appropriate possible diagnostic and therapeutic procedures.
A more detailed explanation of the invention is provided in the following descriptions and claims, and is illustrated in the accompanying drawings.
FIG. 1 is a block diagram of a cardiac pacer analysis system constructed in accordance with the principles of the present invention;
FIG. 2 is a typical device hard copy output of the system of FIG. 1;
FIG. 3 illustrates the structure needed to implement the system of FIG. 1 in a microprocessor-based instrument;
FIG. 4A illustrates a surface ECG;
FIG. 4B illustrates a normal acceptable atrial ICEG signal;
FIG. 4C illustrates an unacceptable atrial ICEG signal;
FIG. 4D illustrates an unacceptable atrial ICEG signal;
FIG. 4E illustrates an unacceptable atrial ICEG signal;
FIG. 5A illustrates an atrial ICEG with a pacing spike and repolarization atrifact;
FIG. 5B illustrates an atrial ICEG after removal of the spike and atrifact;
FIG. 6 illustrates the identification of cardiac activity;
FIG. 7 illustrates the event list formatting;
FIG. 8 illustrates an example event list;
FIG. 9 is an overall flow chart for the paced ECG event analysis unit;
FIG. 10 is a flow chart showing the initialization step of the paced ECG analysis;
FIG. 11 is a flow chart showing the missing event determination step of the paced ECG event analysis;
FIG. 12 is a flow chart showing the updating step of the paced ECG event analysis;
FIG. 13 is a flow chart showing the clinical analysis and advisor unit;
FIG. 14 is a flow chart showing the data reduction and summarization step of the clinical analysis and adviser unit;
FIG. 15A illustrates an event status summary record that would be produced for the surface ECG illustrated in FIG. 15B;
FIG. 15B is an illustration of a sample (stylized) surface ECG;
FIG. 16 is a flow chart showing the problem identification step for the clinical analysis and advisor unit; and
FIG. 17 is a flow chart showing the step of determining problem causes and providing clinical advice by the clinical analysis and advisor unit.
Referring to FIG. 1, the cardiac pacing analysis system of the present invention is embodied in a device including five major functional units:
The device consists of five major functional units:
1. A signal receiving and storage unit 20,
2. A digital signal processing unit 22,
3. A paced ECG event analysis unit 24,
4. A clinical analysis and advisor unit 26, and
5. A results output unit 28.
The signal receiving and storage unit 20 accepts surface ECG and telemetrically transmitted information from the pacemaker and stores it for later use by the remaining units. The next three units analyze the received information; the digital signal processing unit 22 identifies and characterizes the events in the received ECG data, the paced ECG event analysis unit 24 determines if the pacemaker functioned correctly at each event, and the clinical analysis and advisor unit 26 summarizes these results and identifies and observed problems and provides probable causes and possible corrective actions for them. The final unit, the results output unit 28, presents the results of the analyses to the clinician.
FIG. 1 shows how the information flows among the five units of the device, while FIG. 2 shows a typical device hard copy output. FIG. 3 shows the structure needed to implement the device in a microprocessor-based instrument.
The signal receiving and storage unit accepts and stores two types of information.
The first is an array of digital information transmitted from the pacemaker. This includes pacemaker programming information (the specific programmed values of all the pacemaker's programmable parameters), pacemaker stored patient related information (such as implant date, lead type and location, pre-implant symptoms, etc.), and results of automatically performed pacemaker measurements (such as lead impedance or battery level).
The second type of information is a predetermined length of N seconds (up to 30, 8 in preferred implementation) of synchronously sampled electrocardiographic signals, including atrial and ventricular intra-cardiac electrograms, a surface ECG signal, and pacemaker generated activity indicators (telemetered signals which identify specific actions taken by, or changes of state in, the implanted pacemaker, such as paced, sensed, end of refractory, etc.).
The atrial and ventricular intra-cardiac electrograms are sampled by the pacemaker, and digitally transmitted, along with the pacemaker activity indicators, to the device. The surface ECG signal is presented to the device as an analog signal. The devide samples this synchronously with the intra-cardiac electrogram sampling by taking a surface ECG sample at the time of receipt of every other intra-cardiac electrogram sample. The signal sampling sequence is: receive an atrial ICEG sample, receive a ventricular ICEG sample, take a surface ECG sample, receive an atrial ICEG sample, and so on.
The pacemaker activity indicators are transmitted by the pacemaker in lieu of ICEG samples, with a unique identifying code. Each activity indicator takes the place of one sample, so synchrony is maintained. (Note: The digital signal processing unit extracts each indicator from the ICEG data stream, and replaces the "missing" ICEG sample value with an interpolated value.
The pacemakeer stored information is received first, the the combined ICEG, ECG, and activity indicator signals. Processing of the information does not begin until all the signal information has been received and stored. The received ECG/ICEG signals are displayed on a real time analog display for the operator, and are continuously stored in a circular buffer holding N seconds of the digitized signals. When the operator is satisfied with the received signals, he indicates this, and the last N seconds (stored in the buffer) are saved for analysis.
The purpose of the digital signal processing is to convert the continuous stream of digitized analog information into an ordered list of discrete events, and to characterize each event.
An event is defined as any interaction between the pacemaker and the heart, or any cardiac activity which should have caused a pacemaker response. These include (for either channel) spontaneous cardiac activity (whether sensed or not), pacemaker sensing of cardiac activity (whether of valid signal or of noise), pacemaker pacing outputs and cardiac evoked responses.
An event is characterized by a set of quantitative and symbolic metrics, including the time of occurrence, the channel on which it occurred, the presence or absence of spontaneous activity, whether or not the pacemaker sensed, and/or claimed (as shown by an activity indicator) it output a packing pulse, the presence or absence of a pacing pulse in the ECG signals, and the presence or absence of an evoked response. In addition, any other "special" information conveyed by the activity indicators (for example, an PVC indication) is included in the event description.
The presence of other pacemaker state changes which were signaled by an activity indicator (such as the end of a channel's refractory period) are identified, but not as separate events. Every event has appended to it a series of occurrence times, one for each possible pacemaker state change. If a particular state change happened between two events (after event A, but before event B) its time of occurrence in the description of the present event (event A) is set to a positive number, indicating how many milliseconds after the present event it occurred. A time of zero is used to indicate that no such change occurred between the present event and the next one.
The digital signal processing performs a six step process, as follows:
1. Signal sorting, activity indicator identification and removal,
2. ECG (including ICEG) signal verification,
3. Identification and removal of pacing spikes and atrifacts,
4. Detection of cardiac activity,
5. Correlation of cardiac activity and pacing spikes with activity indicators, and
6. Formatting the event list (for further analysis).
The sampled ICEG signals and the pacemaker activity indicators are received as a single multiplexed data stream. This is separated into three signals: the atrial ICEG, the ventricular ICEG, and the activity indicators. This is accomplished based on the known transmission sequence used by the pacemaker, and the unique codes which identify the activity indicators.
Next, since activity indicators are transmitted in place of ICEG signal samples, the ICEG signal timing will be corrected for any missing or time-shifted samples. In addition, since the atrial and ventricular ICEG samples are taken alternately, and the surface ECG samples are taken synchronously with every other transmitted sample (or inserted activity indicator), all sampled data and activity indicators must be corrected to produce a common sampling moment. These two steps are accomplished simultaneously. The result of this step is a set of four synchronously sampled signals; the surface ECG, the atrial and ventricular ICEGs, and the activity indicators. The received signals are sorted and corrected as indicated in the following Chart A:
__________________________________________________________________________CHART ASignal Sorting, Activity Indicator Identification and Removal__________________________________________________________________________A. ICEG and ECG Signals as Received(Assuming 500 sample per second for each signal)Time (msec) 1 2 3 4 5 6 7 8 9 10 11 12 | | | | | | | | | | | |Telemetry DA1 DV1 DA2 DV2 DA3 DV3 DA4 PI1 DA5 DV5 DA6 DV6 | | | | | | | | | | | |Surface ECG S1 S2 S3 S4 S5 S6Where D and P are unique code indentifiers for ICEG data samplesand pacemaker activity indicators, respectively;A1, V1, and S1 are sample number 1 of the Atrial ICEG,Ventricular ICEG, and Surface ECG signals, repectively;and I1 is the code for the pacemaker activity indicator number__________________________________________________________________________B. Stored Uncorrected Signal Data FilesTime A ICEG V ICEG S ECG Act. Ind.__________________________________________________________________________1 A1 -- -- --2 -- V1 S1 --3 A2 -- -- --4 -- V2 S2 --5 A3 -- -- --6 -- V3 S3 --7 A4 -- -- --8 -- -- S4 I19 A5 -- -- --10 -- V5 S5 --11 A6 -- -- --12 V6 S6 --__________________________________________________________________________C. Stored Corrected Signal Data FilesAfter Interpolation of V4, which was missing because of I1,and Correction of Atrial ICEG to Common Sampling Time)Time A ICEG V ICEG S ECG Act. Ind.__________________________________________________________________________2 a1 V1 S1 --4 a2 V2 S2 --6 a3 V3 S3 --8 a4 V4 S4 I110 a5 V5 S5 --12 a6 V6 S6 --__________________________________________________________________________ Where a1 = (A1 + A2)/2 and V4 = (V3 + V5)/2
Before any further processing, the ECG and both ICEG signals are checked to determine if they are "clean" enough for processing. The average and deviation of the signals are checked to determine if the overall signal level and the signal to noise level of each is acceptable, and each signal is checked for amplifier saturation following pacemaker output spikes.
If the signal is unsatisfactory, the user is informed (via the Results Output Unit) that the signal cannot be processed, and why. The device then stops and waits for the user to obtain another time segment of ECG/ICEG signals. FIGS. 4A-4E show examples of acceptable and unacceptable Atrial ICEG signals, with the surface ECG included for reference only. The signals shown are idealized versions for illustrative purposes; they are not real human data.
This step in the process locates and removes from each signal channel the pacing "spikes" and polarization artifacts caused by pacemaker outputs. This enhances the later identification of cardiac activity (either spontaneous or evoked).
Pacing spikes are identified in each channel by the presence of threshold crossings in the signal's derivative with a specified time relationship, based on the known pacemaker output pulse width. These spikes are then matched to pacemaker output activity indicators to determine on which channel the pacemaker output occurred. The time channel and occurrence for each pacing spike is stored, and all the pacing spikes are then removed, with a different method used for each channel.
The pacemaker spiked are removed from the surface channel by subtraction, and then the surface ECG signal is smoothed, by interpolation, to follow the "surrounding" evoked response.
Pacemaker spikes and polarization artifacts are removed from the channel on which the pacing spike occurred in a two step process. First, the pacing spike itself is subtracted. Next, the polarization atrifact is exponentially approximated using a second order linear predictor with a least squares estimator; this exponential is then subtracted. This allows the evoked response to be retained, even through it occurs in the middle of the exponential polarization atrifact.
Finally, pacing spikes due to pacemaker outputs on one channel are similarly removed from the other ICEG channel. In addition, the large "far field" polarization artifacts seen in the atrial channel due to ventricular outputs are exponentially removed.
The result of this sep is a set of ECG/ICEG signals with all pacing artifacts removed, but with all spontaneous and evoked cardiac activity retained. FIGS. 5A-5B illustrate this process. FIG. 5A shows a sampled ICEG (idealized) including a pacing spike and a repolarization atrifact. FIG. 5B shows the results of subtracting the pacing spike and the exponentially approximated repolarization atrifact. The remaining signal (shown as a sine wave) would represent the cardiac activity.
Cardiac activity (either spontaneous or evoked) is detected via a two-step process. First, a simple detector scans each signal channel for possible areas of activity. Next, a "smart" detector scans all three signals simultaneously, looking at each area identified by the simple detector.
The simple detector uses a level threshold to locate areas of possible cardiac activity. It independently scans each signal channel (surface ECG, atrial ICEG, and ventricular ICEG) to locate areas where the signal exceeds a defined threshold. The threshold is determined for each channel based on the mean, deviation, and peak values of the signal in that channel. The locations of these "candidate" areas are stored for use by the "smart" detector. (The primary purpose of this "simple" detector is to reduce the amount of signal the computationally intensive "smart" detector must process.)
The smart detector uses a set of "expectancy" matrices. These prestored matrices essentially contain what the device "expects" each type of event (atrial activity, ventricular activity, and noise) to look like across all three channels over a small sequence of samples. They were obtained by taking the mathematical inverse of "observed" signal matrices. The "observed" matrices were based on the combination of a large number of observations of each type of activity.
The "smart" detector scans each type of expectancy matrix across all three simultaneous signals for each area identified by the "simple" detector, determining a "detector output" for each point in the candidate area. It also determines the first and second moment of the detector output. Based on these results, it selects the most probable identification of each candidate area (atrial activity, ventricular activity, or noise) and identifies the fiducial point (or common time reference point) for each area identified as cardiac activity. FIG. 6 illustrates this process. The upper section shows three (stylized) simultaneous data signals--the surface ECG, the atrial ICEG, and the ventricular ICEG. Immediately below each signal are indicated the "Candidate" areas identified by independently scanning each signal with the simple detector. The lower section shows the output of each of the smart detectors over each identified candidate area. These are obtained by independently scanning each smart detector over all three data signals simultaneously. Note that the outputs of the smart detectors exist only for simple detector identified candidate areas. The bottom line indicates the decision made about each candidate area, based on the relative outputs of the smart detectors. Each candidate area is identified as either atrial activity, ventricular activity, or noise (no cardiac activity).
This step examines each identified occurrence of cardiac activity and attempts to associate it with a previously identified pacemaker action (such as a sense or a pace). For example, cardiac activity on a particular channel immediately following a pacemaker output on that channel would be considered as an evoked response, and would be evidence that the pacemaker output had "captured" the chamber. Those occurrences of cardiac activity which cannot be associated with an appropriate pacemaker activity indicator are retained as separate events. An example of this would be an unsensed P wave.
The last step in the digital signal processing unit is to sequentially sort the identified events, and to write them in a standard format into the "event list". It is this list of discrete events that will be analyzed by the paced ECG event analysis unit. FIG. 7 shows the (stylized) surface ECG and the activity indicators for that section of the data. FIG. 8 is an event list corresponding to the data section of FIG. 7.
The purpose of the paced ECG event analysis unit is to examine each individual event and determine if the pacemaker functioned properly. For example, did it sense (or not sense) spontaneous cardiac activity when it was supposed to, did it output a pacing pulse at the correct time, did the pacing pulse capture the heart (produce an evoked response in the paced chamber), did the refractory periods end on time, were there any occurrences of PVCs, PACs, or special pacemaker mediated events, etc.
As each event is analyzed, several status indicators are determined for each event. These include sensing status, pacing (timing) status, capture status, state change timing (such as end of refractory period) status, and special (PVC, anti-PMT dropped beat, ventricular safety pace beat, etc.) statuses. The possible values for each status indicator include all possible normal and abnormal functional conditions for that pacemaker function. For example, the possible values for sensing status include three normal conditions (OK) and five abnormal conditions (NG), as follows:
______________________________________STATUS MEANING______________________________________OK - Unobserved: No cardiac activity and no sense indicator,OK - Ignored: Cardiac activity properly not sensed,OK - Sensed: Cardiac activity properly sensed,NG - Undersense: Cardiac activity not sensed when it should have been,NG - Oversense: Sense indicator with no cardiac activity,NG - Sense in Off: A sense indicator from a channel with sensing turned off,NG - Sense in A sense indicator during theBlanking: blanking period of a channel,NG - Indicated Sense Sense indicator during specialIn Noise Window noise blanking period.______________________________________
Since is is possible for several abnormal conditions to occur at the same time (for example, an oversense in the blanking period), the unit identifies the most serious problem, and assigns that status indicator value for the event.
The paced ECG event analysis unit is based on a detailed model of the functioning relationships incorporated in the pacemaker's hardware and software, expressed as a set of logical rules. These rules predict exactly what the pacemaker is expected to do in any situation, based on the programmed parameter values. The unit compares the expected functioning (as predicted by the model) with the observed functioning (as evidenced by the event list) to determine the status of each pacemaker function for each event.
The paced ECG event analysis unit performs a five step process, with the last four steps repeated sequentially for each entry in the event list, as follows:
2. "Missing" event detection,
3. Status indicator determination,
4. Update the model, and
5. Check for ("non-event") state change indicators. FIG. 9 shows the overall flow of information in this unit.
In order to determine how the pacemaker should act at a given moment it is necessary to know the "state" of the pacemaker; i.e., the value of every variable in the pacemaker at that moment in time. For example, to determine if the pacemaker should sense a P-wave, it is necessary to know if atrial sensing is on or off, and, if it is on, is the channel blanked, refractory, alert, or in a noise window. The values of these internal pacemaker variables depend on both the programmed parameter values and the past experience (history) of the pacemaker. While all programmed parameter values are known, the history of the pacemaker is not known at the beginning of the ECG/ICEG data segment. Initialization establishes its state.
Initialization is accomplished by assuming that the pacemaker is functioning properly, and examining how it acted in response to the heart's actions early on in the data segment. For example, if a DDD pacemaker's first action was to pace the atrium, then it is assumed to have been in the atrial escape interval at the start of the data segment. Since both the number of possible pacemaker states and the number of first actions are finite (though large), an exhaustive analysis of the responses to initial actions allows the pacemaker's state at the start of the data to be uniquely determined. Once the initial state of the pacemaker has been determined, each subsequent event can then be sequentially analyzed. FIG. 10 shows the sequence of information flow for this unit.
The analysis of each event begins by checking to see if any event should have occurred after the last analyzed event and prior to the specific event that is about to be analyzed; i.e., is any expected event "missing." This can occur for two reasons, pacemaker malfunction or unobserved pacemaker state changes. If a "missing event" is identified, it is inserted into the event list ahead of the event about to be analyzed. The inserted "missing" event will be analyzed next, before the event that was about to be analyzed. Examples of each type of "missing event" follow. FIG. 11 shows the decision structure for identifying "missing" events.
Suppose that a VOO pacemaker is programmed to 60 beats per minute, and that the interval from the previous event (a ventricular pace) to the event about to be analyzed in the event list is 1,200 milliseconds. Obviously, the pacemaker should have output a pulse 1,000 milliseconds after the previous event, and did not--it malfunctioned. This is accommodated by adding an event to the event list at 1,000 milliseconds after the previous event (200 milliseconds before the event that was about to be analyzed). When this "added" event is analyzed, it will indicate a failure to pace when expected.
However, "missing events" can also occur during normal pacemaker functioning. For example, consider a VDD pacemaker. Assume that following a ventricular pace, no atrial activity is detected for the entire minimum rate determined beat to beat interval. The pacemaker would then correctly pace the ventricle. However, the atrial escape interval has ended and the ventricular escape interval (or AV delay) has started with no activity indicator. To allow the model to correctly process this state change, an event would be added to the event list at the expected end of the atrial escape interval. (This is identified as a "phantom" event and is only used internally for analysis; it is not identified as an event to the user.)
Knowing the state of the pacemaker, it is possible to determine if it functional properly at each event. Each event is analyzed, based on the metrics determined by the digital signal processing unit. A single value is assigned to each status for every event.
Separate rules evaluate the various functions and determine the value of each status indicator for the event. A typical rule from the evaluation of capture status might read:
______________________________________IF Pacing output is present and evoked response is presentTHEN Capture status is "OK - captured"______________________________________
The rules used are based on a rigorous, exhaustive analysis of all possible combinations of relevant event metrics and pacemaker programmed parameter values, and were verified by clinical experts. The rules are independent of the channel where the event occurred, except for events such as premature ventricular contractions or retrograde P waves, which can occur only on a specific channel.
Each event may change the state of the pacemaker. This will affect the way in which it responds to the next event. This step in the paced ECG event analysis determines the way in which the state of the pacemaker has been changed by the event just analyzed. In essence, it "updates" the running model of the pacemaker, and prepares it to evaluate the next event. The following Chart B shows the input variables used by, and the possible outcomes for, each set of event status determination rules--sensing, pacing (timing) and capture. Note that the same rules apply to both the atrial and ventricular channels, and are applied independently to each.
______________________________________CHART BStatus Indicator Determination______________________________________A. Sensing StatusInput VariablesSense Amplifier State: Off, Blanked, Refractory, Alert, Noise Window/Possible, Noise Window/DefiniteSpontaneous Cardiac Activity: Absent, PresentSense Activity Indicator: Present, AbsentPossible OutcomesOK - UnobservedOK - IgnoredOK - SensedNG - UndersenseNG - OversenseNG - Sense When OffNG - Sense in BlankingNG - Sense in Noise WindowB. Pacing (Timing) StatusInput VariablesModePacing: Off, OnSensing: Off, OnTriggering: Off, OnEvent Time = End of Escape Interval (within allowed Minimumand Maximum Tolerance): No, Yes, UncertainCorrect Sense (Sense when not Refractory and not in VentricularSafety Pace Window): No, YesPace Activity Indicator: Absent, PresentPossible OutcomesOK - No Output ExpectedOK - No Output Expected/PhantomOK - Output When ExpectedOK - Output Timing UncertainNG - No Output When ExpectedNG - Output When Not ExpectedNG - Output TriggeringNG - Output When OffC. Capturing StatusInput VariablesPace Activity Indicator: Absent, PresentPacing Output Pulse: Absent, PresentSpontaneous Cardiac Activity: Absent, PresentEvoked Response: Absent, PresentPossible OutcomesOK - Unobserved, No Pacer OutputOK - Unobserved, Competitive PacingOK - CapturedNG - No Capture ObservedNG - No Capture, Output Pulse Missing______________________________________
It is based on the detailed model of the pacemaker functional relationships and the programmed parameter values. However, the model has been expended to allow for uncertainties due to both real world timing tolerances and imprecise or incomplete history.
For example, the duration of the AV delay may be a function of whether or not the two previous atrial events were paced or sensed. If this is not shown (such as on the second beat), the model would be updated to show a range of allowable AV delays, based on however much history is known. When the next ventricular event is analyzed, AV delays falling anywhere in this range would be considered correct functioning. FIG. 12 shows the steps involved in updating the pacemaker model, depending on the type of event that has occurred. Note that the process is similar, regardless of the channel on which the event occurred.
Certain state changes within the pacemaker are signaled by telemetered activity indicators, but are not considered as pacemaker/patient events. They were indicated in the event list by noting the time they occurred after the immediately preceding true event. The last step in the analysis of a single event is to look for any such indicators and verify their function and timing. The following Chart C shows the input variables and possible outcomes for a typical state change activity indicator status determination, the end of refractory period activity indicator. Note that the same rules apply to both the atrial and ventricular channels, and are applied independently to each.
______________________________________CHART CState Change Indicator StatusEnd of Refractory (EOR) Activity Indicator Status______________________________________Input VariablesChannel Refractory: No, YesEOR Minimum Time After This Event, Before Next Event:No, YesEOR Nominal Time After This Event, Before Next Event:No, YesEOR Maximum Time After This Event, Before Next Event:No, YesEOR Activity Indicator: Absent, PresentEOR Activity Indicator Time: Less Than EOR Minimum Time, Between Minimum and Maximum. Greater Than EOR MAximum TimePossible OutcomeOK - No EOR Activity Indicator ExpectedOK - EOR Activity Indicator On TimeNG - EOR Activity Indicator EarlyNG - EOR Activity Indiator LateNG - EOR Activity Indicator MissingNG - Extra EOR Activity Indicator______________________________________
This completes the analysis of an event in the event list. The last four steps are repeated until the end of the event list is reached.
The purpose of the clinical analysis and advisor unit is to combine the results of the analyses of the individual events into a single comprehensive evaluation of the implanted cardiac pacemaker system.
Following the paced ECG event analysis, the event list contains the signal analysis metrics and statuses for each patient/pacemaker interaction or event. The clinical analysis and advisor unit uses expert system techniques to combine the information in the event list with patient and pacemaker data, and a knowledge base of clinical expertise in ECG problem solving to produce a summary analysis of the functional condition of the implanted pacemaker; including any identified problem(s), their probable cause(s), and clinically acceptable actions to correct them.
The clinical analysis and advisor unit uses a clinical knowledge base organized into a series of frame-like structures; that is, separate structures for problems relating to pacing leads, pacing rate, pacemaker electronic malfunctions, pacing and sensing thresholds, pacing lead configurations, etc. This allows the unit to search the knowledge base much as a clinician would analyze a paced ECG in actual practice.
This structuring also allows each step of the analysis to be individually examined and validated. Because each structure covers a limited and defined domain (set of possible inputs, problems, and causes) it can be rigorously validated, often by exhaustive search of all possible input combinations and their resulting outputs. This is typically not possible in most expert systems which do not employ such a frame-like structuring.
The clinical analysis and advisor unit uses a four step process, as follows:
1. Data reduction (and summarization),
2. Problem identification,
3. Determination of problem causes, and
4. Provision of clinical advice.
FIG. 13 shows the sequence of events in this unit.
In the present implementation, steps three and four of this process were combined into a single step. Therefore, in the following descriptions, the purposes of these last two steps will be separately described, and then their implementation as a single step will be described.
To allow the clinical analysis and advisor unit to examine and sort out the large amount of information presented to it in any reasonable time, data reduction is necessary. This is accomplished in four separate areas; reduction of programmed parameter and stored patient information values, reduction of strings of events into the larger clinical P-QRS complexes called "beats," identification of clinically significant ECG patterns over multiple events, and summarizing of common event status values. These reductions are accomplished by the sequential application of a series of pre-stored rules or "Productions" in an "IF (FACTS) . . . THEN (ACTIONS) . . . " format, and random access memory search and update methods.
The number of programmable parameter values stored in the pacemaker can cause a combinatorial explosion, results in an unmanageable number of logic tests being needed to arrive at a single analysis result. These programmable parameter values are reduced to a manageable number by symbolic representations. For example, a pacemaker may have up to 128 possible combinations for pacemaker output amplitude and pulse width. This is first reduced by combining the two values into a single value representing the total charge delivered by the output. This might reduce the 128 values by more than half. Next these charge values are ordered and identified as falling into one of five clinically significant symbolically labelled categories. A set of 40 charge values might be labelled as follows:
______________________________________Minimum - Lowest (Value 1)Low - Next 9 (Values 2 through 10)Mid Range - Next 20 (Values 11 through 30)High - Next 9 (Values 31 through 39)Maximum - Highest (Value 40)______________________________________
A similar example is the reduction of the stored implant date and the present date into a single designation of whether the implant is "acute" or "chronic."
The second data reduction is performed primarily to reduce the amount of information that will have to be presented to the clinician. Separate events are combined into larger P-QRS complexes identified as "beats." This allows the conversion of references from the exact time domain into the clinical terms normally used in discussing ECGs. Thus, rather than reporting an atrial event which occurred at 2895 milliseconds into the data segment, the device can refer to the atrial part of P-QRS beat 3. This reduction is accomplished by a set of rules that examine the order and type of atrial and ventricular events within specific time limits.
Productions are also used to combine the order and timing of individual events to identify ECG occurrences that happen over several beats, such as retrograde P waves, premature ventricular contractions, or pacemaker mediated tachycardia. These identifications are added to the individual event descriptions in the Event List before summarization.
At the same time, questionable occurrences are examined and verified. For example, it is not always possible to directly verify atrial capture, since the atrial evoked response is not always clearly identifiable in the ECG or ICEG. Digital signal processing may fail to identify it, with the result theat atrial capture status is classified as "unknown." However, by examining a series of events, there may be "further evidence" indicating atrial capture. If there are instances where atrial paced events are consistently followed by spontaneous ventricular contractions within a normal AV delay range, then atrial capture can be assumed to have occurred, and the atrial capture status is changed to "OK--Captured."
Finally, the entire list of individual events and their separate status values are summarized to produce a single event status summary record. This summary contains, for each channel, the type of event (sensed, paced, etc.) and the common status values found in the different beats. It is this event status summary record, in combination with pacemaker and patient data, which is primarily used for problem identification. FIG. 14 shows the sequential flow of these activities. FIG. 15 shows the event status summary record that would be produced for the sample (stylized) surface ECG shown in FIG. 15B. The record is based on the analysis of all the signals, not just the surface ECG. The surface ECG is included here for illustrative purposes only.
Once the event status summary record has been produced, it is scanned via a computed "key" access (based on the channel, the number of records, and status indicator) to the record, to determine the operational status of each of the pacemaker's functions (sensing, pacing, timing and capture) for each channel. The productions examine the status indicator values for each particular function for all events. Functions are identified as having one of four operational states, as follows:
Unobserved: The particular function was never observable during the ECG data segment. (Example: Atrial sensing when no P waves were present.)
Normal: The particular function was observable at least once during the ECG data segment; and its status was OK every time it was observed. (Example: Proper atrial sensing of intermittent P waves with no over-sensing when P waves not present.)
Abnormal-Intermittent: The particular function was observable at least twice during the ECG data segment; its status was OK at least once and No Good at least once. (Example: Multiple paced atrial beats, with the atrium captured on some beats and not on others.)
Abnormal--Complete (or Constant): The particular function was observable at least once during the ECG data segment; its status was No Good every time it was observed. (Example: One or more paced atrial beats, none of which captured the atrium.)
In addition, any special status indicators are reviewed for possible improper functioning.
Where any abnormal functioning is identified, the beats on which the function's status was No Good are noted. These will be reported to the clinician.
At this stage in its analysis, the device has simply "reviewed" the ECG and "reported" its findings, "flagging" any abnormalities. There has been no identification of the possible causes of any of the observed abnormalities, and no determination of future clinical actions, either diagnostic or therapeutic. In certain applications, this would be the appropriate termination of the analysis. In those cases, the remaining stages in the clinical analysis and advisor unit would be disabled, and the present coded analysis results would be directly passed to the results output unit.
FIG. 16 shows the sequential identification of problems with each of the different pacer functions.
Once individual problems (or malfunctions) have been identified, the device must determine what caused the problem(s). Because of the complex interactions within the implanted system, multiple observed problems may in fact have a common cause. For example, a dislodged atrial lead could cause both intermittent atrial under sensing and complete loss of atrial capture; in the presence of retrograde conduction, this could also yield retrograde P waves. Alternately, consistent atrial undersensing along with complete loss of atrial capture could be due to an atrial lead problem (fracture, dislocation, etc.) or to separately programmed inappropriate values for atrial output and atrial sensitivity.
Problem causes are grouped by engineering system (pacemaker timing control, output circuits, sensing circuits, leads, etc.), with each system being sequentially examined. The stored knowledge base used to identify problem causes is based upon a structured representation of information derived primarily from pacemaker system engineers, and secondarily from experienced clinicians, obtained through both reviews of published material and extensive interviews.
Because specific system malfunctions may cause multiple observed problems, it is necessary to examine not only separate observed problems, but also combinations of problems. To assist in identifying problem causes, stored information (such as pacemaker measurements and stored patient information) as well as programmed parameter values are combined with the information on the observed problems. Where a single cause cannot be positively identified, multiple possible causes are retained.
Once the causes of the observed pacemaker system problems have been identified, possible corrective actions can be identified. Determining the proper action to correct a specific problem is a clinical task, clearly requiring an experienced medical practitioner. The device's ability to recommend actions is severely constrained by both ethical and legal considerations. It is not within the scope of any device to practice clinical medicine. However, it is within the scope of this device to provide the clinician with a set of reminders, encompassing clinically accepted techniques for rectifying each identified problem, along with a list of "relevant" patient and/or pacemaker information.
Another knowledge base (obtained primarily from clinical experts) is used to identify appropriate and generally accepted clinical procedures. These may include both specific actions (such as reprogramming the pacemaker) and diagnostic procedures (such as fluoroscopic examination of the lead). The recommendations are based not only on the observed problem, but also on stored information about the pacemaker and the patient. For example, increasing the pacemaker's output would not be recommended if the pacemaker were already at maximum output, while reducing the pacing rate to attempt to observe atrial sensing would not be recommended if the patient has a pre-pacing history of syncope.
In addition to identifying possible actions, the device also identifies specific facts from the stored information which are relevant to the actions identified. These are passed to the results output unit along with the actions.
In its present implementation, the two separate steps of determination of problem causes the provision of clinical advice have been combined into a single step. The two separate knowledge bases were combined into a common sets of productions with a single inference engine.
As in other units, the productions in this step use the "IF (FACTS) . . . THEN (ACTIONS) . . . " structure. FACTS are the combinations of symbolic representations of the stored pacemaker data, quantitative and symbolic paced ECG event metrics, and the summary of the statuses for each event. Each "FACTS" part of a production essentially represents a possible problem state. The "ACTION" part of a production contains relevant pacemaker programmed variables to be displayed, a statement of both normal and abnormal events and where they occur (P-QRS beats), the probable cause of the abnormal event, some reasoning about the event (if possible) and recommendations for actions to correct the problem.
An example of a production from this step is:
______________________________________IF COMPLETE LOSS of (channel) SENSING and (channel) SENSITIVITY is MAXIMUM and COMPLETE LOSS of (channel) CAPTURE and (channel) OUTPUT is HIGH and (channel) IMPLANT-TIME is ACUTETHENDisplay: (channel) SENSITIVITY valueDisplay: (channel) OUTPUT valueDisplay: "Examine (channel) lead for possible repositioning."Display: "Watch for Diaphragmatic Stimulation due to the HIGH OUTPUT value."______________________________________
The productions are grouped (framed) into problem categories. That is: pacemaker malfunctioning, pacing leads, pacing and sensing thresholds, pacing rate, etc.
The mechanism to search through the entire knowledge base of productions is called an "inference engine." Each production is examined, and if the "FACTS" part is true, then the production is instantiated and the "ACTIONS" occur. If false, then the search continues to process the other productions. The order of the search through the productions emulates the way in which a clinician would view and analyze a patient's paced ECG. FIG. 17 shows the structure of the Expert System that is used for the joint implementation of these two steps, indicating the types of information stored in each section of the data base.
The purpose of the results output unit is to present the conclusions from the analyses to the clinician. Depending on the capabilities of the output unit, results may be presented either as a single entity or as a sequential series of presentations, either on a visual display or in "hard copy."
Regardless of the output mechanism used, the results output unit performs several functions. First, it combines the stored surface ECG with the derived beat identifications and stored activity indicators to provide an annotated ECG. Second, it provides a display of the summarized results for each channel, identifying all observed and unobserved functional status for each channel, with all abnormal findings clearly labelled. Finally, for every abnormal finding, it lists the relevant pacemaker and patient data, the probable causes, and possible corrective actions.
This unit includes large scale editing and code conversion sections, to convert the internal coded information into specific user readable outputs, tailored to the specific display being used, as well as the connectors and drivers for the actual output unit employed.
Although an illustrative embodiment of the invention has been shown and described, it is to be understood that various modifications and substitutions may be made by those skilled in the art without departing from the novel spirit and scope of the present invention.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US4223678 *||3 May 1978||23 Sep 1980||Mieczyslaw Mirowski||Arrhythmia recorder for use with an implantable defibrillator|
|US4550370 *||13 Feb 1985||29 Oct 1985||Medtronic, Inc.||Pacemaker programmer with telemetric functions|
|US4596255 *||15 Feb 1985||24 Jun 1986||Snell Jeffery D||Apparatus for interpreting and displaying cardiac events of a heart connected to a cardiac pacing means|
|US4705042 *||21 May 1985||10 Nov 1987||Cordis Corporation||Pacing system analyzer having provision for direct connection of pacer to pacing leads|
|1||Bernstein, et al., "Notation System and Overlay Diagrams for the Analysis of Paced Electrocardiograms", PACE, vol. 6, pp. 73-80 (Jan.-Feb. 1983).|
|2||*||Bernstein, et al., Notation System and Overlay Diagrams for the Analysis of Paced Electrocardiograms , PACE, vol. 6, pp. 73 80 (Jan. Feb. 1983).|
|3||Dassen, et al., "Evaluation of Pacemaker Performance Using Computer Simulation" PACE, vol. 8, pp. 795-805 (Nov.-Dec. 1985).|
|4||*||Dassen, et al., Evaluation of Pacemaker Performance Using Computer Simulation PACE, vol. 8, pp. 795 805 (Nov. Dec. 1985).|
|5||Manoli, et al., "An Algorithm for Arrhythmia Detection from Epicardial ECG", 37th ACEMB, p. 82 (Sep. 17-19, 1984).|
|6||*||Manoli, et al., An Algorithm for Arrhythmia Detection from Epicardial ECG , 37th ACEMB, p. 82 (Sep. 17 19, 1984).|
|7||Olson, et al., "Pacemaker Diagnostic Diagrams" PACE, vol. 8, pp. 691-700 (Sep.-Oct. 1985).|
|8||*||Olson, et al., Pacemaker Diagnostic Diagrams PACE, vol. 8, pp. 691 700 (Sep. Oct. 1985).|
|9||Sutton, et al., "Interpretation of Dual Chamber Pacemaker Electrocardiograms", PACE, vol. 8, pp. 6-16 (Jan.-Feb. 1985).|
|10||*||Sutton, et al., Interpretation of Dual Chamber Pacemaker Electrocardiograms , PACE, vol. 8, pp. 6 16 (Jan. Feb. 1985).|
|11||Yeh, "Electrogram Evaluation By The Pacemaker Follow-Up Station", Cleveland Clinic Foundation (May 9, 1985).|
|12||*||Yeh, Electrogram Evaluation By The Pacemaker Follow Up Station , Cleveland Clinic Foundation (May 9, 1985).|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US5027814 *||19 May 1989||2 Jul 1991||Ventritex, Inc.||Implantable medical device employing an improved waveform digitization network|
|US5042497 *||30 Jan 1990||27 Aug 1991||Cardiac Pacemakers, Inc.||Arrhythmia prediction and prevention for implanted devices|
|US5226086 *||18 May 1990||6 Jul 1993||Minnesota Mining And Manufacturing Company||Method, apparatus, system and interface unit for programming a hearing aid|
|US5240009 *||25 Mar 1991||31 Aug 1993||Ventritex, Inc.||Medical device with morphology discrimination|
|US5292341 *||2 Mar 1992||8 Mar 1994||Siemens Pacesetter, Inc.||Method and system for determining and automatically adjusting the sensor parameters of a rate-responsive pacemaker|
|US5404877 *||4 Jun 1993||11 Apr 1995||Telectronics Pacing Systems, Inc.||Leadless implantable sensor assembly and a cardiac emergency warning alarm|
|US5507786 *||14 Apr 1994||16 Apr 1996||Pacesetter, Inc.||System and method for measuring and storing parametric data pertaining to operating characteristics of an implantable medical device|
|US5518001 *||17 Jun 1994||21 May 1996||Pacesetter, Inc.||Cardiac device with patient-triggered storage of physiological sensor data|
|US5540232 *||19 Apr 1994||30 Jul 1996||Del Mar Avionics||Method and apparatus for displaying pacer signals on an electrocardiograph|
|US5594638 *||29 Dec 1993||14 Jan 1997||First Opinion Corporation||Computerized medical diagnostic system including re-enter function and sensitivity factors|
|US5605158 *||2 Aug 1995||25 Feb 1997||Pacesetter, Inc.||Apparatus for annotating physiological waveforms|
|US5607460 *||15 Mar 1996||4 Mar 1997||Angeion Corporation||Physician interface expert system for programming implantable arrythmia treatment devices|
|US5660176 *||29 Dec 1993||26 Aug 1997||First Opinion Corporation||Computerized medical diagnostic and treatment advice system|
|US5660183 *||16 Aug 1995||26 Aug 1997||Telectronics Pacing Systems, Inc.||Interactive probability based expert system for diagnosis of pacemaker related cardiac problems|
|US5711297 *||30 Jan 1996||27 Jan 1998||First Opinion Corporation||Computerized medical advice system and method including meta function|
|US5713938 *||12 Nov 1996||3 Feb 1998||Pacesetter, Inc.||Fuzzy logic expert system for an implantable cardiac device|
|US5720771 *||2 Aug 1995||24 Feb 1998||Pacesetter, Inc.||Method and apparatus for monitoring physiological data from an implantable medical device|
|US5724968 *||29 Dec 1993||10 Mar 1998||First Opinion Corporation||Computerized medical diagnostic system including meta function|
|US5758095 *||24 Feb 1995||26 May 1998||Albaum; David||Interactive medication ordering system|
|US5782876 *||15 Apr 1996||21 Jul 1998||Medtronic, Inc.||Method and apparatus using windows and an index value for identifying cardic arrhythmias|
|US5868669 *||9 Jan 1997||9 Feb 1999||First Opinion Corporation||Computerized medical diagnostic and treatment advice system|
|US5891178 *||13 May 1997||6 Apr 1999||Pacesetter, Inc.||Programmer system and associated methods for rapidly evaluating and programming an implanted cardiac device|
|US5948005 *||28 Jan 1997||7 Sep 1999||Pacesetter, Inc.||Multi-event bin heart rate histogram for use with and implantable pacemaker|
|US5954666 *||4 Aug 1995||21 Sep 1999||Pacesetter, Inc.||System for analyzing specific portions of cardiac waveforms|
|US6016442 *||25 Mar 1998||18 Jan 2000||Cardiac Pacemakers, Inc.||System for displaying cardiac arrhythmia data|
|US6021351 *||25 Jun 1999||1 Feb 2000||Cardiac Pacemakers, Inc.||Method and apparatus for assessing patient well-being|
|US6091990 *||3 Nov 1999||18 Jul 2000||Cardiac Pacemakers, Inc.||System for grouping and displaying cardiac arrhythmia data|
|US6113540 *||23 Feb 1999||5 Sep 2000||First Opinion Corporation||Computerized medical diagnostic and treatment advice system|
|US6206829||17 Aug 1999||27 Mar 2001||First Opinion Corporation||Computerized medical diagnostic and treatment advice system including network access|
|US6253102||11 May 2000||26 Jun 2001||Cardiac Pacemakers, Inc.||System for displaying cardiac arrhythmia data|
|US6259950||14 Sep 1999||10 Jul 2001||Pacesetter, Inc.||Implantable stimulation device and method for determining a trial autocapture using backup atrial stimulation|
|US6263244||15 Sep 1999||17 Jul 2001||Pacesetter, Inc.||Implantable stimulation device and method for determining atrial autocapture using PVC response|
|US6270456||7 Jun 1999||7 Aug 2001||First Opinion Corporation||Computerized medical diagnostic system utilizing list-based processing|
|US6289244 *||20 Aug 1999||11 Sep 2001||Cardiac Pacemakers, Inc.||Self audit system|
|US6301503||29 Sep 2000||9 Oct 2001||Cardiac Pacemakers, Inc.||System for grouping and displaying cardiac arrhythmia data|
|US6304778||20 Aug 1999||16 Oct 2001||Cardiac Pacemakers, Inc.||Implantable defibrillators with programmable cross-chamber blanking|
|US6317633||19 Jan 2000||13 Nov 2001||Medtronic, Inc.||Implantable lead functional status monitor and method|
|US6405087||25 Feb 2000||11 Jun 2002||Pacesetter, Inc.||Cardiac stimulation system providing implantable device performance evaluation and method|
|US6482156||5 Mar 2001||19 Nov 2002||First Opinion Corporation||Computerized medical diagnostic and treatment advice system including network access|
|US6594523 *||14 Sep 2001||15 Jul 2003||Pacesetter, Inc.||Implantable stimulation device, programmer, and method for automatically evaluating interaction of the device with a patient's heart|
|US6641532||7 Aug 2001||4 Nov 2003||First Opinion Corporation||Computerized medical diagnostic system utilizing list-based processing|
|US6650944||8 Dec 2000||18 Nov 2003||Medtronic, Inc.||Follow-up monitoring method and system for implantable medical devices|
|US6665558||15 Dec 2000||16 Dec 2003||Cardiac Pacemakers, Inc.||System and method for correlation of patient health information and implant device data|
|US6668188||25 Apr 2001||23 Dec 2003||Cardiac Pacemakers, Inc.||Determination of long-term condition of cardiac patients|
|US6684221 *||8 May 2000||27 Jan 2004||Oracle International Corporation||Uniform hierarchical information classification and mapping system|
|US6687539||16 Oct 2001||3 Feb 2004||Cardiac Pacemakers, Inc.||Implantable defibrillators with programmable cross-chamber blanking|
|US6718198||12 Jul 2001||6 Apr 2004||Cardiac Pacemakers, Inc.||Arrhythmia display|
|US6721594||12 Jul 2001||13 Apr 2004||Cardiac Pacemakers, Inc.||Arrythmia display|
|US6721600||31 Dec 2001||13 Apr 2004||Medtronic, Inc.||Implantable lead functional status monitor and method|
|US6843801||8 Apr 2002||18 Jan 2005||Cardiac Pacemakers, Inc.||Method and system for identifying and displaying groups of cardiac arrhythmic episodes|
|US6849045||19 Nov 2002||1 Feb 2005||First Opinion Corporation||Computerized medical diagnostic and treatment advice system including network access|
|US6873875||29 Aug 2000||29 Mar 2005||Cardiac Pacemakers, Inc.||Implantable pulse generator and method having adjustable signal blanking|
|US6889081||23 Jul 2002||3 May 2005||Cardiac Pacemakers, Inc.||Classification of supraventricular and ventricular cardiac rhythms using cross channel timing algorithm|
|US6950702||15 Jul 2002||27 Sep 2005||Cardiac Pacemakers, Inc.||Use of curvature based features for beat detection|
|US6959213||21 Nov 2002||25 Oct 2005||Intermedics, Inc.||Implantable device with digital waveform telemetry|
|US6980850 *||30 Dec 2002||27 Dec 2005||Pacesetter, Inc.||System and method for emulating a surface EKG using an implantable cardiac stimulation device|
|US6987998||28 Feb 2001||17 Jan 2006||Cardiac Pacemakers, Inc.||Cardiac rhythm management patient report|
|US6993379||30 Dec 2002||31 Jan 2006||Pacesetter, Inc.||System and method for emulating a surface EKG using an implantable cardiac stimulation device|
|US7010349||9 Dec 2003||7 Mar 2006||Cardiac Pacemakers, Inc.||System and method for detecting and displaying parameter interactions|
|US7031764||8 Nov 2002||18 Apr 2006||Cardiac Pacemakers, Inc.||Cardiac rhythm management systems and methods using multiple morphology templates for discriminating between rhythms|
|US7043305||6 Mar 2002||9 May 2006||Cardiac Pacemakers, Inc.||Method and apparatus for establishing context among events and optimizing implanted medical device performance|
|US7047065||16 Oct 2003||16 May 2006||Cardiac Pacemakers, Inc.||System and method for correlation of patient health information and implant device data|
|US7047083||30 Sep 2002||16 May 2006||Medtronic, Inc.||Method and apparatus for identifying lead-related conditions using lead impedance measurements|
|US7113825||3 May 2002||26 Sep 2006||Cardiac Pacemakers, Inc.||Method and apparatus for detecting acoustic oscillations in cardiac rhythm|
|US7117037||27 Jan 2003||3 Oct 2006||Cardiac Pacemakers, Inc.||Event marker alignment by inclusion of event marker transmission latency in the real-time data stream|
|US7136707||21 Jan 2003||14 Nov 2006||Cardiac Pacemakers, Inc.||Recordable macros for pacemaker follow-up|
|US7162301 *||31 Dec 2002||9 Jan 2007||Cardiac Pacemakers, Inc.||Method and system for detecting capture with cancellation of pacing artifact|
|US7181285||26 Dec 2000||20 Feb 2007||Cardiac Pacemakers, Inc.||Expert system and method|
|US7191004||31 Dec 2002||13 Mar 2007||Cardiac Pacemakers, Inc.||Capture verification using an evoked response reference|
|US7191006||5 Dec 2002||13 Mar 2007||Cardiac Pacemakers, Inc.||Cardiac rhythm management systems and methods for rule-illustrative parameter entry|
|US7200436||12 Jul 2004||3 Apr 2007||Cardiac Pacemakers, Inc.||Implantable pulse generator and method having adjustable signal blanking|
|US7277747||23 Nov 2004||2 Oct 2007||Cardiac Pacemakers, Inc.||Arrhythmia memory for tachyarrhythmia discrimination|
|US7286872||7 Oct 2003||23 Oct 2007||Cardiac Pacemakers, Inc.||Method and apparatus for managing data from multiple sensing channels|
|US7289845||12 Dec 2003||30 Oct 2007||Cardiac Pacemakers, Inc.||Curvature based method for selecting features from an electrophysiologic signal for purpose of complex identification and classification|
|US7289851||5 Apr 2004||30 Oct 2007||Medtronic, Inc.||Method and apparatus for identifying lead-related conditions using impedance trends and oversensing criteria|
|US7297111||9 Mar 2005||20 Nov 2007||Clinical Decision Support, Llc||Computerized medical diagnostic and treatment advice system|
|US7300402||20 Feb 2003||27 Nov 2007||Clinical Decision Support, Llc||Computerized medical diagnostic and treatment advice system|
|US7306560||28 Jan 2005||11 Dec 2007||Clinical Decision Support, Llc||Computerized medical diagnostic and treatment advice system including network access|
|US7344496||4 Sep 2003||18 Mar 2008||Clinical Decision Support, Llc||Computerized medical diagnostic system utilizing list-based processing|
|US7383088||7 Nov 2001||3 Jun 2008||Cardiac Pacemakers, Inc.||Centralized management system for programmable medical devices|
|US7406348||27 Apr 2005||29 Jul 2008||Cardiac Pacemakers, Inc.||System and method for displaying a histogram of cardiac events|
|US7418295||22 Dec 2004||26 Aug 2008||Cardiac Pacemakers, Inc.||Method and system for identifying and displaying groups of cardiac arrhythmic episodes|
|US7418296||30 Jul 2004||26 Aug 2008||Cardiac Pacemakers, Inc.||Wireless pacing system analyzer in a programmer system|
|US7468032||18 Dec 2002||23 Dec 2008||Cardiac Pacemakers, Inc.||Advanced patient management for identifying, displaying and assisting with correlating health-related data|
|US7471980||22 Dec 2003||30 Dec 2008||Cardiac Pacemakers, Inc.||Synchronizing continuous signals and discrete events for an implantable medical device|
|US7500955||27 Jun 2003||10 Mar 2009||Cardiac Pacemaker, Inc.||Signal compression based on curvature parameters|
|US7515961||29 Apr 2005||7 Apr 2009||Medtronic, Inc.||Method and apparatus for dynamically monitoring, detecting and diagnosing lead conditions|
|US7539536||21 Mar 2006||26 May 2009||Cardiac Pacemakers, Inc.||Cardiac rhythm management systems and methods using multiple morphology templates for discriminating between rhythms|
|US7580744||11 Mar 2005||25 Aug 2009||Cardiac Pacemakers, Inc.||Classification of supraventricular and ventricular cardiac rhythms using cross channel timing algorithm|
|US7610084||7 Jun 2006||27 Oct 2009||Cardiac Pacemakers, Inc.||System and method for classifying cardiac depolarization complexes with multi-dimensional correlation|
|US7676267||13 Mar 2007||9 Mar 2010||Cardiac Pacemakers, Inc.||Capture verification using an evoked response reference|
|US7702393 *||9 Jan 2007||20 Apr 2010||Cardiac Pacemakers, Inc.||Method and system for detecting capture with cancellation of pacing artifact|
|US7751892||6 May 2004||6 Jul 2010||Cardiac Pacemakers, Inc.||Implantable medical device programming apparatus having a graphical user interface|
|US7769600||31 Oct 2007||3 Aug 2010||Clinical Decision Support||Disease management system and method|
|US7780595||14 May 2004||24 Aug 2010||Clinical Decision Support, Llc||Panel diagnostic method and system|
|US7792571||27 Jun 2003||7 Sep 2010||Cardiac Pacemakers, Inc.||Tachyarrhythmia detection and discrimination based on curvature parameters|
|US7801606||14 Feb 2007||21 Sep 2010||Cardiac Pacemakers, Inc.||Implantable pulse generator and method having adjustable signal blanking|
|US7805199||1 May 2006||28 Sep 2010||Cardiac Pacemakers, Inc.||Method and apparatus for establishing context among events and optimizing implanted medical device performance|
|US7844322||24 Apr 2006||30 Nov 2010||Cardiac Pacemakers, Inc.||System and method for correlation of patient health information and implant device data|
|US7899534||17 Jan 2007||1 Mar 2011||Cardiac Pacemakers, Inc.||Expert system and method|
|US7953488||31 Jul 2008||31 May 2011||Medtronic, Inc.||Pre-qualification of an alternate sensing configuration|
|US7959568||22 Dec 2008||14 Jun 2011||Cardiac Pacemakers, Inc.||Advanced patient management for identifying, displaying and assisting with correlating health-related data|
|US7962203||29 Dec 2003||14 Jun 2011||Cardiac Pacemakers, Inc.||Arrhythmia display|
|US7963924 *||25 Oct 2006||21 Jun 2011||Sorin Crm Sas||Heart simulator|
|US7972275||30 Dec 2002||5 Jul 2011||Cardiac Pacemakers, Inc.||Method and apparatus for monitoring of diastolic hemodynamics|
|US7974690||30 Jun 2008||5 Jul 2011||Medtronic, Inc.||Lead integrity testing during suspected tachyarrhythmias|
|US7974692||31 Aug 2010||5 Jul 2011||Cardiac Pacemakers, Inc.||Implantable pulse generator and method having adjustable signal blanking|
|US7979378||24 Sep 2009||12 Jul 2011||Cardiac Pacemakers, Inc.||Medical device user interface automatically resolving interaction between programmable parameters|
|US7983745||8 Jan 2009||19 Jul 2011||Cardiac Pacemakers, Inc.||Advanced patient management with environmental data|
|US7983759||18 Dec 2002||19 Jul 2011||Cardiac Pacemakers, Inc.||Advanced patient management for reporting multiple health-related parameters|
|US7993267||31 Oct 2007||9 Aug 2011||Clinical Decision Support, Llc||Disease management system including a no response method|
|US8015138||29 Oct 2007||6 Sep 2011||Clinical Decision Support, Llc||Computerized medical self-diagnostic and treatment advice system|
|US8019582||20 Apr 2004||13 Sep 2011||Clinical Decision Support, Llc||Automated diagnostic system and method|
|US8027725||8 Mar 2010||27 Sep 2011||Cardiac Pacemakers, Inc.||Capture verification using an evoked response reference|
|US8032208||8 Jul 2008||4 Oct 2011||Cardiac Pacemakers, Inc.||System and method for displaying a histogram of cardiac events|
|US8043213||18 Dec 2002||25 Oct 2011||Cardiac Pacemakers, Inc.||Advanced patient management for triaging health-related data using color codes|
|US8046060||14 Nov 2005||25 Oct 2011||Cardiac Pacemakers, Inc.||Differentiating arrhythmic events having different origins|
|US8050757||24 Aug 2009||1 Nov 2011||Cardiac Pacemakers, Inc.||Classification of supraventricular and ventricular cardiac rhythms using cross channel timing algorithm|
|US8050762||15 Mar 2010||1 Nov 2011||Jaeho Kim||Method and system for detecting capture with cancellation of pacing artifact|
|US8055516||23 Aug 2010||8 Nov 2011||Clinical Decision Support, Llc||Panel diagnostic method and system|
|US8060378||30 Oct 2007||15 Nov 2011||Clinical Decision Support, Llc||Disease management system and method including question version|
|US8066636||31 Oct 2007||29 Nov 2011||Clinical Decision Support, Llc||Disease management system and method including pain code|
|US8078277||29 Oct 2008||13 Dec 2011||Medtronic, Inc.||Identification and remediation of oversensed cardiac events using far-field electrograms|
|US8099165||15 Feb 2011||17 Jan 2012||Cardiac Pacemakers, Inc.||Expert system and method|
|US8108034||28 Nov 2005||31 Jan 2012||Cardiac Pacemakers, Inc.||Systems and methods for valvular regurgitation detection|
|US8126553||25 Jul 2008||28 Feb 2012||Medtronic, Inc.||Sensing integrity determination based on cardiovascular pressure|
|US8131351||8 Nov 2010||6 Mar 2012||Cardiac Pacemakers, Inc.||System and method for correlation of patient health information and implant device data|
|US8160716||27 Sep 2010||17 Apr 2012||Cardiac Pacemakers, Inc.||Method and apparatus for establishing context among events and optimizing implanted medical device performance|
|US8200322||30 Jul 2008||12 Jun 2012||Medtronic, Inc.||Electrogram storage for suspected non-physiological episodes|
|US8214037||30 Jun 2011||3 Jul 2012||Cardiac Pacemakers, Inc.||Implantable pulse generator and method having adjustable signal blanking|
|US8260407||28 Aug 2006||4 Sep 2012||Pacesetter, Inc.||Intracardiac device and method for storing cardiac test results and associated EGM data|
|US8280508||24 Feb 2009||2 Oct 2012||Cardiac Pacemakers, Inc.||Signal compression based on curvature parameters|
|US8280518||25 Aug 2006||2 Oct 2012||Cardiac Pacemakers, Inc.||Recordable macros for pacemaker follow-up|
|US8287520||10 Apr 2008||16 Oct 2012||Medtronic, Inc.||Automated integrity tests|
|US8301252||16 Jun 2011||30 Oct 2012||Cardiac Pacemakers, Inc.||Advanced patient management with composite parameter indices|
|US8301467||25 Oct 2011||30 Oct 2012||Clinical Decision Support, Llc||Panel diagnostic method and system including active and passive strategies|
|US8315697||31 Oct 2011||20 Nov 2012||Cardiac Pacemakers, Inc.|
|US8321366||7 Jul 2011||27 Nov 2012||Cardiac Pacemakers, Inc.||Systems and methods for automatically resolving interaction between programmable parameters|
|US8337409||31 Oct 2007||25 Dec 2012||Clinical Decision Support Llc||Computerized medical diagnostic system utilizing list-based processing|
|US8386036||15 Dec 2011||26 Feb 2013||Cardiac Pacemakers, Inc.||Expert system and method|
|US8391989||18 Dec 2002||5 Mar 2013||Cardiac Pacemakers, Inc.||Advanced patient management for defining, identifying and using predetermined health-related events|
|US8392217||31 Oct 2007||5 Mar 2013||Clinical Decision Support, Llc||Disease management system and method including preview mode|
|US8396543||28 Jan 2010||12 Mar 2013||Medtronic, Inc.||Storage of data for evaluation of lead integrity|
|US8409107||11 Aug 2010||2 Apr 2013||Cardiac Pacemakers, Inc.||Tachyarrhythmia detection and discrimination based on curvature parameters|
|US8417350||14 Sep 2012||9 Apr 2013||Cardiac Pacemakers, Inc.||Recordable macros for pacemaker follow-up|
|US8437840||26 Sep 2011||7 May 2013||Medtronic, Inc.||Episode classifier algorithm|
|US8463369||13 Jun 2011||11 Jun 2013||Cardiac Pacemakers, Inc.||Arrhythmia display|
|US8521281||14 Oct 2011||27 Aug 2013||Medtronic, Inc.||Electrogram classification algorithm|
|US8543215||18 Feb 2013||24 Sep 2013||Cardiac Pacemakers, Inc.||Advanced patient management for defining, identifying and using predetermined health-related events|
|US8548576||2 Mar 2012||1 Oct 2013||Cardiac Pacemakers, Inc.||System and method for correlation of patient health information and implant device data|
|US8560056||1 Aug 2012||15 Oct 2013||Pacesetter, Inc.||Intracardiac device and method for storing cardiac test results and associated EGM data|
|US8583219||1 Aug 2012||12 Nov 2013||Pacesetter, Inc.||Intracardiac device and method for storing cardiac test results and associated EGM data|
|US8600504||16 Jun 2011||3 Dec 2013||Cardiac Pacemakers, Inc.||Physiologic demand driven pacing|
|US8628470||20 Sep 2011||14 Jan 2014||Clinical Decision Support, Llc||Disease management system and method including medication therapy self-management|
|US8630875||31 Oct 2007||14 Jan 2014||Clinical Decision Support, Llc||Disease management system and health assessment method|
|US8634917||29 Jul 2008||21 Jan 2014||Cardiac Pacemakers, Inc.||Method and system for identifying and displaying groups of cardiac arrhythmic episodes|
|US8636669||5 Jan 2011||28 Jan 2014||Cardiac Pacemakers, Inc.||Method and apparatus for monitoring of diastolic hemodynamics|
|US8639318||29 Oct 2012||28 Jan 2014||Cardiac Pacemakers, Inc.||Advanced patient management with composite parameter indices|
|US8644931||25 Jul 2008||4 Feb 2014||Medtronic, Inc.||Impedance variability analysis to identify lead-related conditions|
|US8663104||31 Oct 2007||4 Mar 2014||Clinical Decision Support, Llc||Disease management system and method including therapeutic alterations permission level|
|US8682694||30 Oct 2007||25 Mar 2014||Clinical Decision Support, Llc||Disease management system and method including permission database|
|US8694116||16 Apr 2012||8 Apr 2014||Cardiac Pacemakers, Inc.|
|US8725242||28 Sep 2011||13 May 2014||Cardiac Pacemakers, Inc.||System and method for displaying a histogram of cardiac events|
|US8727976||31 Oct 2007||20 May 2014||Clinical Decision Support, Llc||Disease management system operating on a network|
|US8727979||31 Oct 2007||20 May 2014||Clinical Decision Support, Llc||Disease management system and method including significant symptom filtering|
|US8731968||29 Oct 2012||20 May 2014||Clinical Decision Support, Llc||Panel diagnostic method and system including automated diagnostic analysis|
|US8738560||6 Nov 2012||27 May 2014||Cardiac Pacemakers, Inc.||Systems and methods for automatically resolving interaction between programmable parameters|
|US8740790||29 Oct 2007||3 Jun 2014||Clinical Decision Support, Llc||Disease management system and method|
|US8744560||30 Sep 2011||3 Jun 2014||Medtronic, Inc.||Electrogram summary|
|US8755897||19 Nov 2007||17 Jun 2014||Cardiac Pacemakers, Inc.||System and method for remote expert-system medical device programming|
|US8774909||26 Sep 2011||8 Jul 2014||Medtronic, Inc.||Episode classifier algorithm|
|US8781585||21 Nov 2011||15 Jul 2014||Medtronic, Inc.||Identification and remediation of oversensed cardiac events using far-field electrograms|
|US8818511||8 Jun 2009||26 Aug 2014||Cardiac Pacemakers, Inc.||Automatic selection of stimulation chamber for ventricular resynchronization therapy|
|US8838220||12 Aug 2013||16 Sep 2014||Cardiac Pacemakers, Inc.||System and method for correlation of patient health information and implant device data|
|US8886296||14 Oct 2011||11 Nov 2014||Medtronic, Inc.||T-wave oversensing|
|US8936555||6 May 2013||20 Jan 2015||The Regents Of The University Of Michigan||Real time clinical decision support system having linked references|
|US9005119||31 Oct 2007||14 Apr 2015||Clinical Decision Support, Llc||Computerized medical diagnostic and treatment advice system including network access|
|US9037240||25 Jul 2008||19 May 2015||Medtronic, Inc.||Electrode lead integrity reports|
|US9061156||17 Jul 2014||23 Jun 2015||Cardiac Pacemakers, Inc.||Automatic selection of stimulation chamber for ventricular resynchronization therapy|
|US9081879||24 Oct 2005||14 Jul 2015||Clinical Decision Support, Llc||Matrix interface for medical diagnostic and treatment advice system and method|
|US20020151809 *||8 Apr 2002||17 Oct 2002||Cardiac Pacemakers, Inc.||Method and system for identifying and displaying groups of cardiac arrhythmic episodes|
|US20020156389 *||28 Feb 2001||24 Oct 2002||Cardiac Pacemakers, Inc.||Cardiac rhythm management patient report|
|US20030088290 *||7 Nov 2001||8 May 2003||Spinelli Julio C.||Centralized management system for programmable medical devices|
|US20040010200 *||15 Jul 2002||15 Jan 2004||Sweeney Robert J.||Use of curvature based features for beat detection|
|US20040064161 *||30 Sep 2002||1 Apr 2004||Gunderson Bruce D.||Method and apparatus for identifying lead-related conditions using lead impedance measurements|
|US20040082976 *||16 Oct 2003||29 Apr 2004||Cardiac Pacemakers, Inc.||System and method for correlation of patient health information and implant device data|
|US20040093035 *||8 Nov 2002||13 May 2004||Mark Schwartz||Cardiac rhythm management systems and methods using multiple morphology templates for discriminating between rhythms|
|US20040111131 *||5 Dec 2002||10 Jun 2004||Bo Hu||Cardiac rhythm management systems and methods for rule-illustrative parameter entry|
|US20040122294 *||18 Dec 2002||24 Jun 2004||John Hatlestad||Advanced patient management with environmental data|
|US20040122295 *||18 Dec 2002||24 Jun 2004||John Hatlestad||Advanced patient management for triaging health-related data using color codes|
|US20040122297 *||18 Dec 2002||24 Jun 2004||Stahmann Jeffrey E.||Advanced patient management for identifying, displaying and assisting with correlating health-related data|
|US20040122484 *||18 Dec 2002||24 Jun 2004||John Hatlestad||Advanced patient management for defining, identifying and using predetermined health-related events|
|US20040122485 *||18 Dec 2002||24 Jun 2004||Stahmann Jeffrey E.||Advanced patient management for reporting multiple health-related parameters|
|US20040122486 *||18 Dec 2002||24 Jun 2004||Stahmann Jeffrey E.||Advanced patient management for acquiring, trending and displaying health-related parameters|
|US20040122487 *||18 Dec 2002||24 Jun 2004||John Hatlestad||Advanced patient management with composite parameter indices|
|US20040127792 *||30 Dec 2002||1 Jul 2004||Siejko Krzysztof Z.||Method and apparatus for monitoring of diastolic hemodynamics|
|US20040127806 *||12 Dec 2003||1 Jul 2004||Cardiac Pacemakers, Inc.||Curvature based method for selecting features from an electrophysiologic signals for purpose of complex identification and classification|
|US20040127949 *||31 Dec 2002||1 Jul 2004||Jaeho Kim||Method and system for detecting capture with cancellation of pacing artifact|
|US20040127950 *||31 Dec 2002||1 Jul 2004||Jaeho Kim||Capture verification using an evoked response reference|
|US20040143304 *||21 Jan 2003||22 Jul 2004||Hall Jeffrey A.||Recordable macros for pacemaker follow-up|
|US20040219600 *||12 Dec 2003||4 Nov 2004||Williams Robert Wood||Method for determining sensitivity to environmental toxins and susceptibility to parkinson's disease|
|US20040230232 *||14 Jan 2004||18 Nov 2004||Cardiac Pacemakers, Inc.||Implantable defibrillators with programmable cross-chamber blanking|
|US20040230456 *||14 May 2003||18 Nov 2004||Lozier Luke R.||System for identifying candidates for ICD implantation|
|US20040243194 *||12 Jul 2004||2 Dec 2004||Cardiac Pacemakers, Inc.||Implantable pulse generator and method having adjustable signal blanking|
|US20040252078 *||13 Jun 2003||16 Dec 2004||Fischer Jonathan H.||Bi-directional interface for low data rate application|
|US20050033385 *||6 May 2004||10 Feb 2005||Peterson Les Norman||Implantable medical device programming apparatus having a graphical user interface|
|US20050107840 *||22 Dec 2004||19 May 2005||Cardiac Pacemakers, Inc.||Method and system for identifying and displaying groups of cardiac arrhythmic episodes|
|US20050137627 *||22 Dec 2003||23 Jun 2005||Koshiol Allan T.||Synchronizing continuous signals and discrete events for an implantable medical device|
|US20050137636 *||5 Apr 2004||23 Jun 2005||Gunderson Bruce D.||Method and apparatus for identifying lead-related conditions using impedance trends and oversensing criteria|
|US20050154616 *||9 Mar 2005||14 Jul 2005||Iliff Edwin C.||Computerized medical diagnostic and treatment advice system|
|US20050159781 *||11 Mar 2005||21 Jul 2005||Cardiac Pacemakers, Inc.|
|US20050165285 *||28 Jan 2005||28 Jul 2005||Iliff Edwin C.||Computerized medical diagnostic and treatment advice system including network access|
|US20050187588 *||27 Apr 2005||25 Aug 2005||Cardiac Pacemakers, Inc.||System and method for displaying cardiac events|
|US20060025830 *||30 Jul 2004||2 Feb 2006||Scott Freeberg||Wireless pacing systems analyzer in a programmer system|
|US20060058850 *||7 Oct 2003||16 Mar 2006||Kramer Karen M||Method and apparatus for managing data from multiple sensing channels|
|US20060111643 *||23 Nov 2004||25 May 2006||Shelley Cazares||Arrhythmia memory for tachyarrhythmia discrimination|
|US20060135855 *||3 Dec 2003||22 Jun 2006||Koninklijke Philips Electronics N.V.||Method for determining normal measurements for a patient|
|US20060211949 *||7 Jun 2006||21 Sep 2006||Cardiac Pacemakers, Inc.||System and method for classifying cardiac depolarization complexes with multi-dimensional correlation|
|US20060247706 *||29 Apr 2005||2 Nov 2006||Germanson Nancy M||Method and apparatus for dynamically monitoring, detecting and diagnosing lead conditions|
|USRE43433||24 Mar 2009||29 May 2012||Clinical Decision Support, Llc||Computerized medical diagnostic and treatment advice system|
|USRE43548||24 Mar 2009||24 Jul 2012||Clinical Decision Support, Llc||Computerized medical diagnostic and treatment advice system|
|EP0669841A1 *||25 Aug 1994||6 Sep 1995||Siemens Pacesetter, Inc.||Programming system for a patient's cardiac signal|
|EP0756877A2 *||1 Aug 1996||5 Feb 1997||Pacesetter, Inc.||Decision support system and method for an implantable cardiac stimulating device|
|EP0773038A2 *||30 Oct 1996||14 May 1997||Telectronics N.V.||Improved graphic interface for pacemaker programmers|
|WO2002018009A1||26 Aug 2000||7 Mar 2002||Medtronic Inc||Implantable lead functional status monitor and method|
|WO2003077822A2||27 Dec 2002||25 Sep 2003||Medtronic Inc||Imd lead status monitor method and system|
|WO2005056109A1 *||1 Dec 2004||23 Jun 2005||Medtronic Inc||Method and apparatus for identifying lead-related conditions using impedance trends and oversensing criteria|
|WO2006118762A1||12 Apr 2006||9 Nov 2006||Medtronic Inc||Method and apparatus for dynamically monitoring, detecting and diagnosing lead conditions|
|WO2015123483A1||13 Feb 2015||20 Aug 2015||Medtronic, Inc.||Lead monitoring frequency based on lead and patient characteristics|
|U.S. Classification||607/27, 706/924|
|Cooperative Classification||Y10S706/924, A61N1/37252|
|19 Oct 1987||AS||Assignment|
Owner name: TELECTRONICS N.V., DE RUYTERKADE 58A CURACAO, NETH
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:SASMOR, LOUIS;SMITH, EDWARD D.;REEL/FRAME:004769/0627
Effective date: 19870925
Owner name: TELECTRONICS N.V.,NETHERLANDS ANTILLES
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SASMOR, LOUIS;SMITH, EDWARD D.;REEL/FRAME:004769/0627
Effective date: 19870925
|19 Jan 1988||AS06||Security interest|
|19 Jan 1988||AS||Assignment|
Owner name: SOUTHEAST BANK, N.A., MIDLAND BANK PLC (SINGAPORE
Free format text: SECURITY INTEREST;ASSIGNOR:TELECTRONICS, N.V.,;REEL/FRAME:004837/0510
Effective date: 19880105
|5 Dec 1988||AS||Assignment|
Owner name: TELECTRONICS N.V., NETHERLANDS ANTILLES
Free format text: RELEASED BY SECURED PARTY;ASSIGNOR:SOUTHEAST BANKN.A., MIDLAND BANK PLC AND CREDIT LYONNAIS;REEL/FRAME:005002/0786
Effective date: 19880615
|30 Jun 1992||AS||Assignment|
Owner name: TELECTRONICS PACING SYSTEMS, INC., COLORADO
Free format text: ASSIGNORS HEREBY CONFIRMS THE ENTIRE INTEREST IN SAID INVENTIONS TO ASSIGNEE ELECUTED ON SEPT. 16,1988;ASSIGNORS:TELECTRONICS PTY. LTD.;MEDICAL TELECTRONICS HOLDING & FINANCE CO.;TELECTRONIC NV;AND OTHERS;REEL/FRAME:006172/0028
Effective date: 19920622
|24 Sep 1992||FPAY||Fee payment|
Year of fee payment: 4
|17 Oct 1996||FPAY||Fee payment|
Year of fee payment: 8
|5 Nov 1996||AS||Assignment|
Owner name: TELECTRONICS PACING SYSTEMS, INC., COLORADO
Free format text: CORRECTIVE ASSIGNMENT TO CORRECT ASSIGNEE S STATE OF INCORPORATION. AN ASSIGNMENT WAS PREVIOUSLY RECORDED AT REEL 6172, FRAME 0028;ASSIGNORS:TELECTRONICS PTY. LTD., AN AUSTRALIAN COMPANY;MEDICAL TELECTRONICS HOLDING & FINANCE CO. (BV), A DUTCH COMPANY;TELECTRONICS NV, A COMPANY OF THE NETHERLANDS ANTILLES;AND OTHERS;REEL/FRAME:008321/0072
Effective date: 19961101
|21 Mar 1997||AS||Assignment|
Owner name: PACESETTER, INC., CALIFORNIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TELECTRONICS PACING SYSTEMS;REEL/FRAME:008454/0461
Effective date: 19961129
|1 Nov 2000||FPAY||Fee payment|
Year of fee payment: 12